Add abstractions for Clock and Timer

framework/aster-frame/src/arch/x86/timer/jiffies.rs

@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use core::{
+    sync::atomic::{AtomicU64, Ordering},
+    time::Duration,
+};
+
+use super::TIMER_FREQ;
+
+/// Jiffies is a term used to denote the units of time measurement by the kernel.
+///
+/// A jiffy represents one tick of the system timer interrupt,
+/// whose frequency is equal to [`TIMER_FREQ`] Hz.
+#[derive(Copy, Clone, Debug)]
+pub struct Jiffies(u64);
+
+pub(super) static ELAPSED: AtomicU64 = AtomicU64::new(0);
+
+impl Jiffies {
+    /// Creates a new instance.
+    pub fn new(value: u64) -> Self {
+        Self(value)
+    }
+
+    /// Returns the elapsed time since the system boots up.
+    pub fn elapsed() -> Self {
+        Self::new(ELAPSED.load(Ordering::Relaxed))
+    }
+
+    /// Gets the number of jiffies.
+    pub fn as_u64(self) -> u64 {
+        self.0
+    }
+
+    /// Gets the `Duration` calculated from the jiffies counts.
+    pub fn as_duration(self) -> Duration {
+        Duration::from_millis(self.0 * 1000 / TIMER_FREQ)
+    }
+}
+
+impl From<Jiffies> for Duration {
+    fn from(value: Jiffies) -> Self {
+        value.as_duration()
+    }
+}